Idiopathic scoliosis is a disease in which the spine develops a progressive curvature. Its cause is unknown, and if untreated it may result in gross deformity. Approximately one person in five-hundred suffers from this disease. The overall purpose of this investigation is (1) to develop better understanding of the mechanical factors involved in the initiation and progression of idiopathic scoliosis and (2) to apply this information to improve the methods of treatment and to develop means of prevention. Because of the difficulty of dealing with the anatomical complexity of the vertebral column, a basic feature of this program is the use of a computer-generated analog of the spine. Studies of model scoliotic spines will be made in conjunction with clinical studies to provide vital information regarding the three-dimensional morphology of the curves, their progression, and their correction. The knowledge gained from these studies will help to base treatment on more rational and objective grounds, and the understanding provided may be essential to the discovery of its etiology.